The present invention relates to a plasma processing device and an operation method for the plasma processing device. The plasma processing device and the operation method are a plasma processing device and a plasma processing method in which a process to manufacture a semiconductor integrated circuit is used, and a substrate-like sample such as a semiconductor wafer disposed in a processing chamber in a vacuum vessel is processed by using plasma formed in the processing chamber. The plasma processing device and the operation method detect a film thickness or a processing amount of a sample surface by using light emission from the inside of the processing chamber detected during the processing.
A process to manufacture a semiconductor device includes processing to form a circuit pattern of a semiconductor device, so-called dry-etching processing, by etching a film structure including a plurality of film layers including a dielectric material and a mask layer formed on a sample surface by disposing a substrate-like sample of such as a semiconductor wafer in a processing chamber in a vacuum vessel and using plasma formed in the processing chamber. In such etching processing, it is desired to further accurately determine an etching end point and appropriately control processing conditions to realize a recently increasing integration degree of a semiconductor device and to realize a highly accurate circuit pattern by stopping the processing at a desirable film thickness or a desired etching depth of the above-described film layer.
In general, in such etching processing, in a state in which a semiconductor wafer is disposed in a processing chamber in a vacuum vessel, an electric field or a magnetic field is supplied to processing gas supplied in the processing chamber, and plasma is formed by exciting atoms or molecules of the gas. The processing on a film structure on a sample is performed by using the plasma. During the processing, light intensity of a specific wavelength included in light emission of the plasma in the processing chamber is changed in association with an etching progress of a specific film to be processed or a certain film on which the processing is progressing.
Therefore, conventionally, as a technique to accurately detect an end point of the processing, a technique is known which detects a change in intensity of the specific wavelength included in a light emission from a processing chamber during etching processing and detects an end point of the processing based on a result of the above detection. However, the above-described light emission generally includes light emission of relatively less correlated wavelengths other than light emission of a specific wavelength generated by reaction significantly correlated to the processing. When the end point is determined, it is necessary to reduce and suppress miss-detection due to a change in a waveform of a wavelength to be detected, which is caused by such noise.
JP-2014-72264-A describes a technique to accurately detect a change in the intensity of light emission in association with the noise. This conventional technique uses a plasma processing device which performs etching processing on a sample disposed in a processing chamber disposed in a vacuum vessel by using plasma formed in the processing chamber. JP-2014-72264-A discloses a plasma processing device to determine an etching processing amount based on a result in which in-phase components changed by time in an increase or decrease direction together by synchronizing between light emission intensity of a plurality of wavelengths are removed from data of the light emission intensity detected from output from a light receiver which receives light emission from the inside of the processing chamber. Especially, in an example described herein, time-series data indicating the intensity of light emission of a plurality of wavelengths obtained from a spectroscope is sent to an in-phase component removing device to remove the in-phase components. Then, after average components are removed from a difference in data for each time, a characteristic vector is calculated which includes a base corresponding to the in-phase components by performing a principal component analysis about a matrix including data of each wavelength as an element.
Further, a base vector calculated from the characteristic vector is sent to a Kalman filter, in-phase components are removed from a difference in each of the above-described wavelengths by the Kalman filter, and the difference from which the in-phase components are removed is integrated and restored as a time waveform for each wavelength. In the conventional technique, time-series data is used which is restored by removing noise component described above and which indicates light emission intensity, and a technique to highly accurately detect an etching amount or an etching end point is indicated.